JP6540552B2 - Fuel cell single cell - Google Patents

Description

  The present invention relates to a single fuel cell.

  Conventionally, a solid electrolyte fuel cell single cell using a solid electrolyte as an electrolyte is known.

  For example, in Patent Document 1 mentioned above, a porous plate-like metal substrate, a current collecting member provided so as to partially project from one surface of the metal substrate, and a metal substrate so as to cover the current collecting member An anode disposed on one side, a solid electrolyte layer disposed on the anode, and an air pole disposed on the solid electrolyte layer, and the current collector protrudes so as to extend beyond the layer thickness of the anode. A single fuel cell is disclosed.

Patent No. 5564862

  However, in the case of the conventional single fuel cell, since the current collection member penetrates the anode, the reaction point in the anode decreases, and it is difficult to improve the output.

  The reaction function and the diffusion function are separated by securing the reaction point by controlling the pore diameter at the anode and tilting the pore diameter so that the pore diameter increases from the solid electrolyte layer side to the opposite side. There is also a method to However, in a single fuel cell having an anode of such a configuration, as the operation time increases, the conductive material whose shape is changed in the anode by the redox reaction is likely to be absorbed by the layer having a large pore diameter. As a result, the electron conduction path in the anode is interrupted, making it difficult to stably operate for a long time.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a single unit fuel cell that can be operated stably for a long time with high output.

One aspect of the present invention is an anode (2),
At least one current collector (3) projecting from one side of the anode;
A porous support (4) disposed on one side of the anode and covering one side of the anode from which the current collector protrudes;
A solid electrolyte layer (5) disposed on the other side of the anode;
And a cathode (6) disposed on the opposite side to the anode side in the solid electrolyte layer.

  In the unit cell, the current collector protrudes from one side of the anode. And one side of the anode from which a current collection part protrudes is covered by the support body. In the unit cell of the fuel cell, since the current collector is formed outside the anode, it is not necessary to reduce the reaction site in the anode. Therefore, the single fuel cell can secure a sufficient reaction site in the anode. Therefore, the fuel cell single cell can extract the electricity generated at the reaction site with low loss through the current collector, and can improve the output. Further, in the unit cell of the fuel cell, the current collector formed on one side of the anode functions as an electron conduction path of the anode. Therefore, the unit cell of the fuel cell can suppress interruption of the electron conduction path on the anode side, and can stably operate for a long time.

  The reference numerals in parentheses described in the claims and the means for solving the problems indicate the correspondence with the specific means described in the embodiments described later, and the technical scope of the present invention is limited. It is not a thing.

1 is a perspective view schematically showing a single fuel cell of Embodiment 1. FIG. It is sectional drawing which showed typically the II-II line cross section in FIG. It is explanatory drawing which expanded and showed a part of sectional drawing of FIG. 2 typically. It is sectional drawing which showed typically the IV-IV line | wire cross section in FIG. FIG. 5 is an explanatory view schematically showing an enlarged part of a cross-sectional view of FIG. 4; It is explanatory drawing for demonstrating the relationship between the ratio of the electroconductive material which exists in the interface of an anode and a current collection part, and the ratio of the electroconductive material which exists in the inside of an anode. It is explanatory drawing for demonstrating the calculation method of the effective area rate of a current collection part. FIG. 6 is a perspective view schematically showing a single fuel cell of Embodiment 2. It is sectional drawing which showed typically the IX-IX line cross section in FIG.

(Embodiment 1)
The single fuel cell of Embodiment 1 will be described with reference to FIGS. 1 to 7. As illustrated in FIGS. 1 to 7, the single fuel cell 1 of the present embodiment has an anode 2, a current collector 3, a support 4, a solid electrolyte layer 5, and a cathode 6. ing. A fuel cell using solid oxide ceramics as the solid electrolyte of the solid electrolyte layer 3 is referred to as a solid oxide fuel cell (SOFC). The fuel cell single cell 1 can have a flat cell structure. In each of the drawings, an example is shown in which the outer shape of the single fuel cell 1 is square.

  The anode 2 is usually porous and includes pores 21 as illustrated in FIGS. 3 and 5. Specifically, the anode 2 can be configured to include a conductive material and a solid electrolyte material. In this case, the conductive material is a material constituting an electron conduction path in the anode 2. On the other hand, the solid electrolyte material is a framework material constituting an ion conduction path in the anode 2. As a conductive material used for the anode 2, Ni, a Ni alloy, etc. can be illustrated, for example. Examples of solid electrolyte materials used for the anode 2 include zirconium oxide-based oxides such as yttria stabilized zirconia (YSZ) and scandia stabilized zirconia (ScSZ). In this embodiment, specifically, a mixture of Ni and yttria stabilized zirconia can be used as the material of the anode 2.

  The thickness of the anode 2 can be preferably 10 μm or more, more preferably 15 μm or more, from the viewpoint of reaction durability, handleability, processability, and the like. The thickness of the anode 2 can be preferably 30 μm or less, more preferably 25 μm or less, from the viewpoint of reducing electrode reaction resistance and the like.

  The current collector 3 protrudes from one surface of the anode 2. The anode 2 can be configured, for example, in a flat layer, and the current collector 3 specifically protrudes from one side of the layered anode 2 on the support 4 side. A part of the surface of the current collector 3 is connected to one side of the anode 2.

  At least one current collecting unit 3 may be provided. In each of the drawings, an example in which the fuel cell single cell 1 has a plurality of current collectors 3 is shown. Each current collection unit 3 can be configured to extend linearly along one surface of the anode 2, for example, and can be arranged in a mutually separated state. According to this configuration, it is possible to obtain the fuel cell single cell 1 that can easily collect current uniformly in the in-plane direction of the anode 2 by each current collection unit 3. In each of the drawings, an example is shown in which at least one end of each of the linearly extending current collectors 3 is exposed to the cell end surface so that electricity on the anode 2 side can be taken out at the cell end surface. ing.

  Specifically, the current collection unit 3 can be configured to include a conductive material. As a conductive material used for the current collection part 3, Ni, a Ni alloy, etc. can be illustrated, for example. Specifically, Ni can be used as the conductive material of the current collector 3 in the present embodiment.

  When both the current collector 3 and the anode 2 contain a conductive material, the ratio of the conductive material present at the interface 23 between the current collector 3 and the anode 2 is the same as that of the conductive material present inside the anode 2. The configuration can be larger than the ratio. According to this configuration, the electron conduction path by the current collector 3 becomes reliable, and it is easy to suppress the break of the electron conduction path on the anode 2 side, and it is easy to obtain the fuel cell single cell 1 which can be stably operated for a long time Become. In addition, the magnitude relation between the above-mentioned respective proportions can be grasped as follows. As illustrated in FIG. 6, using a scanning electron microscope, the region A at the interface 23 between the current collector 3 and the anode 2 and the region B inside the anode 2 are cross-sectionally observed (× 1000), Line analysis of any 50 μm width by EDX measurement. By comparing the obtained line analysis patterns, it is possible to determine the magnitude relationship between the above-mentioned respective proportions.

Specifically, the difference between the linear thermal expansion coefficient of the conductive material contained in the current collector 3 and the linear thermal expansion coefficient of the conductive material contained in the anode 2 should be 1 × 10 ⁻⁶ / K or less Can. In this case, it is difficult for the current collector 3 to separate from the anode 2 due to expansion and contraction due to heat during long-term operation, and it becomes easy to obtain a single fuel cell 1 capable of stable long-term operation.

The difference in linear thermal expansion coefficient is preferably 0.9 × 10 ⁻⁶ / K or less, more preferably 0.8 × 10 ⁻⁶ / K, from the viewpoint of the adhesion between the current collector 3 and the anode 2 or the like. Or less, more preferably 0.7 × 10 ⁻⁶ / K or less, still more preferably 0.6 × 10 ⁻⁶ / K or less, still more preferably 0.5 × 10 ⁻⁶ / K or less it can. In addition, the difference of the said linear thermal expansion coefficient is fundamentally measured based on JISR1618: 2002 "the measuring method of the thermal expansion by the thermomechanical analysis of fine ceramics." Specifically, a sample of the same material as the conductive material contained in the current collector 3 and a sample of the same material as the conductive material contained in the anode 2 are prepared. Each sample is set in the fully expandable thermal mechanical analyzer, and the temperature is raised at a heating rate of 10 ° C./min. Each sample expands from length L ₀ to L ₁ until the temperature T rises from T ₀ (= 100 ° C.) to T ₁ (= 700 ° C.). Each line thermal expansion coefficient at this time (/ K), respectively calculated from the calculation formula _{(dL / dT) T = T1} / L 0. _{However, (dL / dT) T =} T1 , the temperature T is the slope of the long curve at the time of _{T 1.} The difference in linear thermal expansion coefficient is calculated from the absolute value of the difference in linear thermal expansion coefficient of each of the obtained samples.

  Specifically, the current collection unit 3 can be configured to include a continuous portion continuously connected along one surface of the anode 2. According to this configuration, it is possible to obtain a fuel cell single cell 1 that can easily extract electricity along one side of the anode 2. In addition, the current collection part 3 may contain a discontinuous part in part in the range which can be drive | operated stably for a long time. In the discontinuous portion, adjacent continuous portions are electrically connected to each other through the conductive material in the anode 2, so that the break of the electron conduction path does not occur.

  The form of the continuous portion can be, for example, a configuration in which a plurality of hemispherical portions are connected along one surface of the anode 2 as shown in each drawing. In such a continuous part where a plurality of hemispherical parts are connected, by operating the fuel cell single cell 1 for a long time, the material forming the current collector 3 repeatedly changes in form, and becomes a stable hemispherical shape. It can be formed utilizing the phenomenon that it tries to do.

  Specifically, the ratio of the length of the continuous portion included in current collection unit 3 is larger than the ratio of the connection length of the conductive material in any plane in anode 2 parallel to one surface of anode 2 It can be done. This configuration is confirmed by cross-sectional observation of the fuel cell single cell 1 and comparing the ratio of the length of the continuous portion to the observation length and the ratio of the connection length of the conductive material to the observation length. be able to.

  The amount of protrusion of the current collector 3 can be preferably 1 μm or more, more preferably 3 μm or more, and still more preferably 5 μm or more from the viewpoint of electrical conductivity and the like. The amount of protrusion of the current collector 3 can be preferably 30 μm or less, more preferably 20 μm or less, and still more preferably 10 μm or less from the viewpoint of cell strength and the like. The projection amount of the current collector 3 is obtained by observing the cross-section (× 1000 times) of the interface 23 between the current collector 3 and the anode 2 using a scanning electron microscope. It is an average value of each measured value at the time of measuring protrusion length.

  The width of the current collector 3 can be preferably 20 μm or more, more preferably 50 μm or more, and still more preferably 100 μm or more from the viewpoint of current collection improvement, ease of formation, and the like. The width of the current collecting portion 3 can be preferably 1000 μm or less, more preferably 500 μm or less, and further preferably 200 μm or less from the viewpoint of cell strength and the like. Further, the pitch of the current collecting portion 3 can be preferably 50 μm or more, more preferably 100 μm or more, and still more preferably 400 μm or more from the viewpoint of cell strength, ease of formation, and the like. The pitch of the current collecting portion 3 can be preferably 5000 μm or less, more preferably 2000 μm or less, and still more preferably 1000 μm or less, from the viewpoint of improving the current collecting property and the like.

  The surface 31 excluding the surface 30 connected to the anode 2 in the current collector 3 can be covered by the air gap 32. According to this configuration, the air gap 32 is present along the current collector 3 disposed on one surface of the anode 2. Therefore, the air gap 32 can be functioned as a diffusion flow path when diffusing the fuel gas supplied to the anode 2 in the in-plane direction. Further, the air gap 32 can also function as a discharge flow path for discharging the water vapor generated at the anode 2 by the power generation reaction. Furthermore, since the current collecting portion 3 is covered by the air gap 32, it becomes difficult for the current collecting portion 3 to be in contact with the large pores contained in the support 4. Therefore, although the change of the current collection part 3 arises by oxidation-reduction reaction, it can prevent that the conductive material of the current collection part 3 moves to the support body 4, and can stabilize electrical conductivity. The air gap 32 can be formed, for example, as follows. A current collector forming material is formed of an oxide of a conductive material used for the current collector 3. At this time, the current collector forming material has a volume obtained by combining the volume of the current collector 3 and the volume of the air gap 32. By reducing the formed current collection portion forming material in a reducing atmosphere, the oxide of the conductive material can be made a conductive material, and the void 32 covering the current collection portion 3 can be formed by the volume contraction occurring at this time.

  An air gap 32 exists between the current collector 3 and the support 4. As illustrated in each drawing, a part of the anode 2 may be exposed in the air gap 32. In addition, a portion 33 of the material forming the current collection unit 3 may be attached to the wall surface of the air gap 32 on the support 4 side.

  The support 4 is disposed on one side of the anode 2 and covers one side of the anode 2 from which the current collector 3 protrudes. The support 4 is porous and includes pores 41 as illustrated in FIGS. 3 and 5. However, in order to diffuse the fuel gas supplied to the anode 2, the porosity of the support 4 is made sufficiently larger than the porosity of the anode 2. That is, the anode 2 is denser than the support 4.

  Examples of the material of the support 4 include zirconia, magnesia, alumina and the like. Examples of zirconia include, for example, zirconia-based oxides such as yttria-stabilized zirconia and scandia-stabilized zirconia. In this case, it is easy to reduce the difference in thermal expansion with other materials of the cell, and it is easy to obtain a single fuel cell with little warpage. In the present embodiment, specifically, yttria-stabilized zirconia can be used as the material of the support 4. In addition, since the support body 4 does not need to have electroconductivity, it does not need to contain an electroconductive material, but it can also contain an electroconductive material.

  The thickness of the support 4 can be preferably 100 μm or more, more preferably 200 μm or more, and more preferably 300 μm or more from the viewpoint of securing cell strength and the like. The thickness of the support 4 can be preferably 800 μm or less, more preferably 700 μm or less, from the viewpoint of improving gas diffusivity and the like.

  The solid electrolyte layer 5 is disposed on the other side of the anode 2.

  As a material of the solid electrolyte layer 5, zirconium oxide-based oxides such as yttria-stabilized zirconia and scandia-stabilized zirconia can be suitably used from the viewpoint of being excellent in strength, thermal stability and the like. Yttria-stabilized zirconia is preferable as the material of the solid electrolyte layer 5 from the viewpoint of ion conductivity, mechanical stability, compatibility with other materials, and chemical stability from the air atmosphere to the fuel gas atmosphere, etc. is there. In the present embodiment, specifically, yttria-stabilized zirconia can be used as the material of the solid electrolyte layer 3.

  The thickness of the solid electrolyte layer 5 can be preferably 3 to 20 μm, more preferably 4 to 15 μm, and still more preferably 5 to 10 μm from the viewpoint of reduction of ohmic resistance and the like.

  The cathode 6 is disposed on the side of the solid electrolyte layer 5 opposite to the side of the anode 2. In the present embodiment, the outer shape of the cathode 6 is smaller than the outer shape of the anode 2. In each of the drawings, the outer shapes of the support 4, the anode 2, the solid electrolyte layer 5 and the intermediate layer 7 (described later) are all the same size.

Examples of the material of the cathode 6 include transition metal perovskite oxides. Specific examples of the transition metal perovskite oxide include, for example, La _x Sr _1-x CoO ₃ system oxide, La _x Sr _1-x Co _y Fe _1-y O ₃ system oxide, Sm _x Sr _{1 -x} CoO ₃ based oxide (However, in the above, 0 ≦ x ≦ 1,0 ≦ y ≦ 1) and the like can be exemplified. These can be used alone or in combination of two or more. In this embodiment, specifically, La _x Sr _1-x Co _y Fe _1-y O ₃ based oxide (0 ≦ x ≦ 1, 0 ≦ y ≦ 1) may be used as the material of the cathode 6. it can.

  The thickness of the cathode 6 can be preferably 20 to 100 μm, more preferably 30 to 80 μm from the viewpoint of gas diffusivity, electrode reaction resistance, current collecting property, and the like.

  The fuel cell unit cell 1 can further have an intermediate layer 7 between the solid electrolyte layer 5 and the cathode 6 as illustrated in each drawing. The intermediate layer 7 is a layer mainly for suppressing the reaction between the solid electrolyte layer material and the cathode material.

As a material of the intermediate layer 7, for example, CeO ₂ or CeO ₂ is doped with one or more elements selected from Gd, Sm, Y, La, Nd, Yb, Ca, and Ho, etc. Examples of such a cerium oxide-based oxide such as a ceria-based solid solution can be given. These can be used alone or in combination of two or more. In the present embodiment, specifically, a ceria-based solid solution in which Gd is doped to CeO ₂ can be used as the material of the intermediate layer 7.

  The thickness of the intermediate layer 7 can be preferably 1 to 20 μm, more preferably 2 to 5 μm, from the viewpoints of reduction of ohmic resistance, suppression of element diffusion from the cathode, and the like.

  In the present embodiment, in the fuel cell single cell 1, the support 4 described above, the anode 2, the solid electrolyte layer 5, the intermediate layer 7, and the cathode 6 are stacked in this order and joined together.

  In the single fuel cell 1, the effective area ratio of the current collector 3 to the effective generation area of the cell can be in the range of 3% to 30%. In this case, the current collection efficiency on the anode 2 side by the current collection unit 3 is good, the bonding property between the support 4 and the anode 2 is high, and the fuel cell is easy to suppress peeling between the support 4 and the anode 2 A single cell 1 is obtained. The effective area ratio of the current collector 3 is preferably 3% or more, more preferably 5% or more, still more preferably 7% or more, and still more preferably 10% or more from the viewpoint of improvement of current collection efficiency etc. Can. The effective area ratio of the current collector 3 is preferably 25% or less, more preferably 20% or less, from the viewpoint of securing the bonding site between the support 4 and the anode 2 sufficiently and easily securing the gap 32. More preferably, it can be 18% or less, still more preferably 15% or less.

  The effective area ratio of the current collector 3 will be described with reference to FIG. FIG. 7 shows the positional relationship between the cathode 6, the anode 2, and the current collector 6 when the fuel cell unit cell 1 is viewed from the cathode 6 side. The power generation effective area of the cell refers to the area of a portion in which three layers of anode 2 / solid electrolyte layer 5 / cathode 6 are stacked in a uniform manner. In the present embodiment, the anode 2 and the solid electrolyte layer 5 have the same area, and the area of the cathode 6 is smaller than the area of the anode 2. Therefore, in the present embodiment, the power generation effective area of the cell matches the area of the cathode 6 shown in FIG. On the other hand, the effective area of the current collection part 3 means the area of the part in which the current collection part 3 is formed in the electric power generation effective area of a cell. In the present embodiment, the total area (the hatched portion in FIG. 7) of the current collectors 3 arranged in the area of the cathode 6 is the effective area of the current collectors 3. The effective area ratio (%) of the current collector 3 can be calculated from the formula of 100 × effective area of the current collector 3 / power generation effective area of the cell.

  In the single fuel cell 1, the current collector 3 protrudes from one surface of the anode 2. Then, one surface of the anode 2 from which the current collector 3 protrudes is covered by the support 4. In the unit cell 1 of the fuel cell, since the current collector 3 is formed outside the anode 2, the reaction site in the anode 2 does not have to be reduced. Therefore, the single fuel cell 1 can secure a sufficient reaction site in the anode 2. Therefore, the fuel cell single cell 1 can extract the electricity generated at the reaction site with low loss through the current collector 3 and can improve the output. In addition, in the unit cell 1 of the fuel cell, the current collection unit 3 formed on one surface of the anode 2 functions as an electron conduction path of the anode 2. Therefore, the fuel cell single cell 1 can suppress interruption of the electron conduction path on the anode 2 side, and can stably operate for a long time.

Second Embodiment
A single fuel cell of Embodiment 2 will be described with reference to FIGS. 8 and 9. In addition, the code | symbol same as the code | symbol used in already-appeared embodiment among the code | symbols used after Embodiment 2 represents the component similar to the thing in already-appeared embodiment etc., unless shown otherwise.

  As illustrated in FIG. 8 and FIG. 9, the fuel cell single cell 1 of the present embodiment has an end face electrode 8 electrically connected to each current collector 3 on at least one cell end face. The other configuration is the same as that of the first embodiment.

  Since the fuel cell unit cell 1 has the end face electrode 8 on at least one cell end face, the electricity collected by each current collector 3 can be taken out collectively from the end face electrode 8. So, according to the fuel cell single cell 1, it is excellent in the extraction property of the electricity in a cell end surface. Further, since the fuel cell single cell 1 can connect the electricity collected by the current collector 3 to the outside through the end face electrode 8, the fuel cell single cell 1 can be electrically connected in a fuel cell stack having a plurality of fuel cell single cells 1. It is advantageous to simplify the connection structure.

  Specifically, in the present embodiment, the outer shape of the fuel cell unit cell 1 is square. Therefore, there are six cell end faces. In each of the drawings, an example is shown in which the end face electrode 8 is formed on one of six cell end faces. The end of each current collection unit 3 is exposed at the cell end surface where the end surface electrode 8 is formed, and the end of each current collection unit 3 is electrically connected to the end surface electrode 8. Thus, electricity can be reliably received from the current collectors 3 to the end surface electrodes 8.

  As a material of the end face electrode 8, it is preferable to use a material that is more difficult to oxidize than the material forming the current collector 3. In this case, the form stability of the end face electrode 8 against oxidation and reduction is improved, and the electricity collected by the current collector 3 can be reliably extracted to the outside. Therefore, a single fuel cell 1 with excellent connection reliability can be obtained. In addition, since the end face electrode 8 is not easily oxidized during a long operation, the reliability of the long operation can be enhanced. In addition, since the conductive material is not required for the support 4, there is a wide choice of materials for the support 4. Therefore, it is possible to obtain the fuel cell single cell 1 having advantages such as improvement of cell strength by strength improvement of the support 4 and cost reduction by not using the conductive material for the support 4. The other effects and advantages are the same as in the first embodiment.

  The material of the end face electrode 8 which is more difficult to oxidize than the material forming the current collector 3 can be selected with reference to an Elingham diagram or the like. Specific examples of the material of the end face electrode 8 include W, Mo, Cu, Au, Ag, Pt group, and alloys of these.

  The end face electrode 8 may be provided so as to contact only the support 4 at the cell end face, or may be provided so as to contact the support 4 and the anode 2. Further, a part of the end face electrode 8 may be present in the pores 41 of the support 4. In this case, the bonding property of the end face electrode 8 to the cell end face can be improved. A part of the end face electrode 8 may also exist in the pores 21 of the anode 2 and the gap 32.

(Experimental example)
Hereinafter, it demonstrates more concretely using an experimental example.
<Fuel cell single cell of sample 1>
-Material preparation-
A slurry was prepared by mixing 8YSZ powder (average particle size: 0.5 μm), carbon (pore forming agent), polyvinyl butyral, isoamyl acetate and 1-butanol in a ball mill. The above-described slurry was applied in a layer form on a resin sheet using a doctor blade method, dried, and then the resin sheet was peeled off to prepare a support-forming sheet. The thickness of the support forming sheet was 110 μm. The above average particle diameter is the particle diameter (diameter) d50 when the volume-based cumulative frequency distribution measured by the laser diffraction / scattering method indicates 50% (the same applies hereinafter).

  NiO powder (average particle size: 0.6 μm), 8YSZ powder (average particle size: 0.2 μm), carbon (pore-forming agent), polyvinyl butyral, isoamyl acetate and 1-butanol mixed in a ball mill The slurry was prepared by The mass ratio of NiO powder to 8YSZ powder is 65:35. The above-described slurry was applied in a layer form on a resin sheet using a doctor blade method, and dried to prepare an anode forming sheet with a resin sheet. The thickness of the anode forming sheet was 30 μm. The amount of carbon in the sheet for forming an anode is small compared to the sheet for forming a support.

  After stirring NiO powder (average particle size: 0.6 μm), ethylcellulose (binder), dihydroterpineol acetate (solvent), dispersant, leveling agent, anti-settling agent with a planetary mixer, it is kneaded with a triple roll. Thus, a current collector forming paste was prepared. The paste for current collection part formation was pattern-printed on the surface of the sheet | seat for anode formation on a resin sheet using the screen-printing method. The printing pattern here is a linear pattern composed of 71 linear pastes arranged at equal intervals, and is for forming a plurality of linear current collectors. The line width of each linear paste was 100 μm, the line pitch was 1000 μm, and the line thickness was 80 μm. After drying each linear paste, the resin sheet was peeled off to prepare an anode forming sheet with a current collector forming paste on which a linear pattern of the current collector forming paste is printed on one side thereof.

  A slurry was prepared by mixing 8YSZ powder (average particle size: 0.2 μm), polyvinyl butyral, isoamyl acetate and 1-butanol in a ball mill. The above-mentioned slurry was applied in a layer form on a resin sheet using a doctor blade method, dried, and then the resin sheet was peeled off to prepare a sheet for forming a solid electrolyte layer. The thickness of the solid electrolyte layer-forming sheet was 5.0 μm.

A slurry was prepared by mixing 10 mol% Gd-doped CeO ₂ (10 GDC) powder (average particle size: 0.3 μm), polyvinyl butyral, isoamyl acetate, 2-butanol and ethanol in a ball mill . The above-mentioned slurry was applied in a layer form on a resin sheet using a doctor blade method, dried, and then the resin sheet was peeled off to prepare a sheet for intermediate layer formation. The thickness of the intermediate layer forming sheet was 4.0 μm.

A paste for forming a cathode was prepared by kneading LSC (La _0.6 Sr _0.4 CoO ₃ ) powder (average particle size: 2.0 μm), ethyl cellulose and terpineol with a triple roll.

  Cu powder (average particle size: 0.5 μm), acrylic resin (binder), dihydroterpineol acetate (solvent), dispersant, leveling agent, anti-settling agent after being stirred by a planetary mixer After kneading, dihydroterpineol acetate (solvent) was added, and the mixture was stirred by a planetary mixer to prepare a paste for end face electrode formation.

  A sheet for forming a support, a sheet for forming an anode with a paste for forming a current collection portion, a sheet for forming a solid electrolyte layer, and a sheet for forming an intermediate layer were laminated in this order and pressure-bonded. In addition, the printing surface of the linear pattern in the sheet for anode formation with paste for current collection part formation is arrange | positioned at the sheet | seat side for support body formation. Moreover, the CIP molding method was used for pressure bonding. At this time, CIP molding conditions were a temperature of 80 ° C., a pressure of 50 MPa, and a pressure time of 10 minutes. The obtained crimped body was punched into a square shape to obtain a laminate. The resulting laminate was degreased. In addition, the paste for current collection part formation is exposed to two opposing end surfaces among four end surfaces of a laminated body.

  The laminate was fired at 1350 ° C. for 2 hours in the air. Thus, a sintered body in which a support (200 μm), an anode (20 μm), a solid electrolyte layer (3 μm), and an intermediate layer (3 μm) were laminated in this order was obtained. On the surface of the anode on the support side in the obtained sintered body, a plurality of dense current collector formation members made of NiO were protruded corresponding to the linear pattern. Moreover, the said several current collection part formation material was formed in the state which bited in into the support body by the said crimping | compression-bonding. Moreover, the current collection part formation material was exposed to two opposing end surfaces among four end surfaces of a sintered compact. At this point, no gap was formed between the current collector forming material embedded in the support and the support.

  A cathode-forming paste was applied by screen printing to the surface of the intermediate layer in the above-mentioned sintered body, and baked (baked) in an air atmosphere at 950 ° C. for 2 hours to form a layered cathode (50 μm). In addition, the external shape of the cathode was formed smaller than the external shape of the anode. Thus, a flat cell was obtained.

  The end face electrode forming paste was applied to one of the cell end faces where the current collector forming material in the obtained cell is exposed, using a dip coating method. At this time, the solid electrolyte layer, the intermediate layer and the cathode were masked so as not to apply the end face electrode forming paste. Thus, the end face electrode forming paste was applied to the end face of the support and the end face of the anode among the cell end faces. The end face electrode forming paste was impregnated into the pores of the support from the end face of the support.

  The support on which the end face electrode forming paste was applied and the anode were exposed to a reducing atmosphere, and the solid electrolyte layer, the intermediate layer and the cathode were not exposed to the reducing atmosphere. Then, the support and the anode to which the paste for forming the end face electrode was applied were subjected to reduction treatment under conditions of 800 ° C. for 12 hours in a reducing atmosphere with hydrogen gas. Thereby, NiO contained in the current collection part formation material was reduced, and the current collection part comprised from Ni was formed. In addition, NiO contained in the anode was reduced to Ni. Further, Cu contained in the end face electrode forming paste was combined with Ni formed in the anode to form a conductive path and to form an end face electrode. Thus, a single fuel cell of Sample 1 was obtained.

  In the unit cell of the fuel cell of Sample 1, the surface of the current collector excluding the surface connected to the anode was covered by the void formed by shrinkage of NiO by about 40%. Moreover, in the fuel cell single cell of sample 1, one end of the current collector was connected to the end face electrode. Further, in the unit cell of the fuel cell of Sample 1, the effective area ratio of the current collector to the power generation effective area of the cell was 10%.

  The fuel cell single cell of sample 2 and the fuel of sample 3 are prepared by variously changing the conditions for pattern-printing the current collector forming paste on the surface of the anode forming sheet in the preparation of the fuel cell single cell of sample 1. A single battery cell and a single fuel cell of sample 4 were obtained. The effective area ratio of the current collection part to the power generation effective area of the cell was 20% for the fuel cell single cell of sample 2, 25% for the fuel cell single cell of sample 3, and 30% for the fuel cell single cell of sample 4. . When the effective area ratio of the current collector exceeded 30%, the bonding surface between the support and the anode tended to decrease. Therefore, it was confirmed that it is easy to obtain the fuel cell single cell 1 that is advantageous for suppressing the separation between the support 4 and the anode 2 by setting the effective area ratio of the current collection portion to 30% or less. In addition, as the effective area ratio of the current collector increased, the gap covering the current collector tended to decrease. Therefore, it was confirmed that it is desirable to set the effective area ratio of the current collector to 20% or less from the viewpoint of sufficiently securing the gap covering the current collector.

  In addition, in preparation of the fuel cell single cell of the samples 1-4, the paste for current collection part formation is pattern-printed on the surface of the sheet | seat for anode formation. Therefore, in each single fuel cell, the ratio of the conductive material (Ni) present at the interface between the current collector and the anode is greater than the ratio of the conductive material (Ni) present inside the anode, as described above. It can be said that EDX measurement is clear without performing line analysis.

  The present invention is not limited to the above embodiments and experimental examples, and various modifications can be made without departing from the scope of the invention. In addition, each configuration shown in each embodiment can be arbitrarily combined with each other in each embodiment.

1 Fuel Cell Single Cell 2 Anode 3 Collector 4 Support 5 Solid Electrolyte Layer 6 Cathode

Claims (7)

An anode (2),
At least one current collector (3) projecting from one side of the anode;
A porous support (4) disposed on one side of the anode and covering one side of the anode from which the current collector protrudes;
A solid electrolyte layer (5) disposed on the other side of the anode;
And a cathode (6) disposed on the side of the solid electrolyte layer opposite to the anode side.   The fuel cell single cell according to claim 1, wherein the surface (31) of the current collection portion excluding the surface (30) connected to the anode is covered by an air gap (32). Both the current collector and the anode contain a conductive material,
The fuel cell single cell according to claim 1 or 2, wherein the ratio of the conductive material present at the interface (23) between the current collector and the anode is larger than the ratio of the conductive material present inside the anode. . The difference between the linear thermal expansion coefficient of the conductive material contained in the current collecting portion and the linear thermal expansion coefficient of the conductive material contained in the anode is 1 × 10 ⁻⁶ / K or less. Fuel cell single cell.   The fuel cell single cell according to any one of claims 1 to 4, wherein an end face electrode (8) electrically connected to the current collecting portion is provided on at least one cell end face.   The fuel cell single cell according to claim 5, wherein the material of the end face electrode is a material that is more difficult to oxidize than the material forming the current collection portion.   The fuel cell single cell according to any one of claims 1 to 6, wherein the effective area ratio of the current collection portion to the power generation effective area of the cell is 3% or more and 30% or less.

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